This study documents behaviours of people with HIV/AIDS regarding the disclosure of their HIV-positivity when seeking dental care. An anonymous survey was conducted in Québec, Canada, from 1993 to 1995, using a sample of 463 people with HIV/AIDS recruited from different sources. Over 80% of respondents reported having sought dental care since becoming aware of their positivity. Of these, 54% reported having always disclosed their HIV-positivity to dentists, while 25% reported never having disclosed this information to dentists. However, 83% of all respondents preferred that the dentist be aware of their HIV status. Respondents gave reasons related to the sociopathological impact of HIV infection to explain their behaviours. The predictors of disclosure of HIV-positivity to the dentist were: gender, main source of payment for dental care, prior disclosure of HIV status to family members, prior disclosure of HIV status to co-workers, and trust in the maintenance of confidentiality by the dentist. These results emphasize the need to use universal precautions in the dental office and to promote dentist-patient relations free of discrimination, so that people with HIV/AIDS are not reluctant to disclose their health status and are confident that such disclosure will lead to care best adapted to their condition.